Lifting device operated by bellows

ABSTRACT

A reversible lifting device has an inflatable and deflatable bellows as a drive and catches which engage in recesses of a guide pole. A rigid frame which can be connected to the load acts as one abutment for the bellows. A double-ended lever arm is pivotably mounted on the frame, has the other bellows abutment at one end and one of the catches at its other end.

United States Patent Inventor Appl. No. Filed Patented LIFTING DEVICE OPERATED BY BELLOWS Walter Finkbeiner [56] References Cited 729 Wittlensweilerstr, Freudenstadt, UNITED STATES PATENTS 3232 2,657,009 10/1953 Neis 254/109x Oct. 3,1968 3,273,859 9/1966 Walli 254/109X Mar. 16, 1971 Primary Examiner0thell M. Simpson Assistant Examiner-David R. Melton Attorney-Milton Robert Kestenbaum ABSTRACT: A reversible lifting device has an inflatable and 10 Claims, 7 Drawing Figs.

U.S.Cl 254/93, deflatable bellows as a drive and catches which engage in 254/110 recesses of a guide pole. A rigid frame which can be con- Int. Cl B66f3/24, nected to the load acts as one abutment for the bellows. A B66f 1/04 double-ended lever arm is pivotably mounted on the frame, Field of Search 254/2, 89, has the other bellows abutment at one end and one of the 93, 108-1 1 1; 92/34, 40 catches at its other end.

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PATENTED m1 619?! SHEET 5 OF 5 INVENTOR. W44 7m Hangar/51g /8 Ayala/MW LWTING DEVTCE OPERATED BY BELLOWS The invention relates to a lifting device having inflatable and deflatable bellows as a drive and catches, which engage in recesses of guide poles and can reverse the direction of movement of said lifting device. Lifting devices of this kind require four guide poles on which two platforms can be moved up and down. Depending on whether the upper or lower platform is stationary whenthe bellows are inflated or deflated, the entire apparatus moves upwards or downwards. The bellows need to be very large as they act directly upon the platforms. The entire apparatus is also designed so that it can only be operated when stationary and cannot be conveyed, for example, by a lorry. In the known apparatus the guide poles must run exactly parallel to one another in order that the catches of the lifting device do not disengage thereby'deforming the guide poles. The aim of the invention is to provide a lifting device which can bear considerably weights, but which is nevertheless so small that it can be conveyed by motor vehicles and also carried by a person. In this connection it is intended that the lifting device can be both pushed and pulled.

This problem is solved in accordance with the invention because the lifting device guided along a single guide pole has a rigid frame which can be connected to the load to be shifted and which acts as an abutment of the bellows comprises one end of a two-armed lever which is pivotably mounted on the frame and bears one of the catches on its opposite end.

This lever then acts simultaneously as a guide for the bellows which can be assembled principally from spring-loaded bellows basically known in motor vehicles.

The invention is described in more detail with the aid of an exemplary embodiment shown in the drawing.

FIG. 1 shows a side view of a lifting device having a toothed pole,

FIG. 2 shows the lifting device of FIG. 1 when the bellows are deflated,

FIG. 3 shows the lifting device with the bellows inflated;

FIG. 4 shows a rear view of the lifting device,

H6. 5 shows a plan view of the lifting device,

FIG. 6 shows the entire lifting apparatus,

FIG. 7 shows an arrangement having four lifting devices.

The lifting device comprises essentially a frame 3, bellows 1 with a base plate 2 and a cover plate 4, a pair of guide rails 24 connected to the frame 3, an upper catch and a lower catch 19, said catches alternately engaging in the toothed pins 18 of a pole l7.

The lifting device also has a system of levers which consists of a fork-shaped lever arm 10, connecting the upper catch 15 to the bellows, and a pair of guide joints 22 which are in'turn joined to the upper section 26 of the frame 3 and connected by their opposite ends to a double joint 9 on which the lever arm 10 engages and which itself engages on the cover plate 4 of the bellows. The double joint 9 is rotatably mounted in a bearing lug 5 of the cover plate 4, The compressed air is delivered to the bellows by an air-release valve 8 which is fastened to the base 2 of the same and connected to a pneumatic tube 6 by a tube coupling 7. The lifting device is slidably fastened to two pairs of guide jaws 35 on the toothed pole 17 which consists of two double U-shaped rails 41 (FIGS. 4, 5). The guide jaws 35 gripping the U-shaped section are arranged so as to be pivotable outwards and, for this purpose, are supported on two tubular portions 34 which are rotatably mounted on both sides of the toothed pole in two bearings 33 and 33a. On each of the upper ends of the two tubes 34 is mounted a lever 36 by which the tubular portions can be rotated and the guide jaws 35 swung out. The upper ends of the tubular portions 343 and the bearings 33a associated therewith are provided with slots 39, into which the levers 36, when pivoting downwards with their link plates 38, are in serted when the guide jaws swing inwards. Undesirable pivoting outwards of the guide jaws 35 is thereby surely prevented.

The lifting device operates as follows:

The bellows are deflated in the position shown in FIG. 2, in which case they are pressed together by a pair of tension springs 23 held between the joints 22 and the frame 3. In this position the lower catch 19 is supported on toothed pins 18 of the pole 17, whereas the upper catch 15 is lifted clear from these pins and is therefore free. Then a control lever 28 on the housing is pivoted into the position up, whereby a cam 29 is turned into the horizontal position and lies against a pawl 30 rotatably mounted with its fork-shaped upper end on a pin 14 which is secured to the upper catch 15 and guided through slots 25 on both sides of the two guide rails 24. The pin 14 rotatably connected to the lever arm 10 is in the uppermost position. The lever arm 10 is in turn joined to the frame 3 by a pair of tie rods 11, in which case a first pin 13 constitutes the connection with the lever arm 10 and a second pin 12 the connection with the frame 3.

If compressed air is then passed into the bellows 1, then the latter presses the lever arm 10 upwards which,-when rotating about the pin 13, swings downwards with its upper end, and thus brings the catch 15 connected thereto to bear against the toothed pins 18. Further expansion of the bellows causes the pin 13 to move upwards and therefore the frame connected thereto by the tie rods 11 to be drawn upwards. The lower catch 19, which like the upper catch 15 is provided with a 1'0- tary spring (not shown) drawing the catches against the toothed pole, slides past the toothed pin 18 during this stroke. If the bellows are then deflated by the air-release valve 8, the frame would move downwards; however this is prevented by the lower catch 19 engaging in the toothed pin 18. Thus only the upper catch 15 is drawn back into its uppermost position determined by the slots 25 by the contracting bellows.

It can be easily seen that, when compressed air is reintroduced into the bellows, the operation described is repeated and the lifting device therefore moves upwards another stage. As is readily apparent, by repeating the lifting operation in this manner, the lifting device is made to move upwards, stage by stage or step by step.

If the lifting device is then to be lowered, the control lever 28 is swung into the down position whereupon the cam 29 is turned into a vertical position. The pawl 30 subject to the action of an unshown spring pivots towards the cam 29 as can be seen in FIG. 2 which shows the lifting device in a starting position for the release of air. The load in this case lies on the lower catch 19. A second pawl 31 rotatable in the frame 3 beats under the action of an unshown spring against the upper catch 15 and under its projection 32.

Then the bellows are inflated so that the lever arm 10 again swings upwards, and the pawl 30 joined to the other end of the lever arm 10 moved downwards. However after the catch 15 is blocked by the pawl 31, it pivots away from the toothed pole. When the lever arm ll) swings further upwards the pawl 3i, the surface of which becomes more and more inclined, finally slides beyond the projection 32 of the upper catch so that, the latter immediately bears against the toothed pole due to the action of its rotary spring and can therefore bear the load. The lower catch 19 is thereby relieved of the load and the teeth 58 of the pawl 30 are then engaged with a projection 32a of the lower catch 19.

Then the bellows are again deflated whereby the pin 14 moves upwards with the upper catch 15 in the slot. The lower catch 19 is in this way kept open by the pawl 30. As deflation continues, the upper catch 15 moves gradually upwards, and consequently also the pawl 30, which finally slides over the projection 32a and releases the lower catch 19, so that the latter can again pivot against the toothed pole and accommodate the load. In this position the upper catch 15, as already described, is again pivoted away from the toothed pole and the cycle can be repeated until the required lowering distance is covered.

If the control lever 28 is then set again in the position up, the cam 29 swings against the pawl fit) so that the latter is pivoted away from the lower catch 19 and the pawl 3B is also pressed away from the upper catch 15. The two pawls 3t and 31 are thereby disengaged and the lifting device again moves upwards when the bellows are inflated.

On the top and bottom of the lifting device there are suspension eyelets 27 in which the load can be suspended.

F IG. 6 shows an embodiment wherein the toothed pole 17 is provided with a base plate 43. A support 44 is provided to receive a replaceable platform 46; this support slides with a sliding piece 45 along the toothed pole and is connected by a pin 47 to the lifting device. This arrangement permits the platform 46 to be lowered as far as the base. However the lifting device can also be positioned below the sliding piece. In this case the pin 47 is passed through a second hole 48 on the bottom half of the sliding piece 45. Moreover, in the sliding piece 45 there is a pawl 49 which is pressed by a spring 50 against the toothed pole 17 thereby bearing the load so that, if need be, the lifting device fitted with two handles 52 can be removed and is free to be used for other purposes. The pawl 4& can be secured by a plug 51. The base plate 43 is provided with rollers 53 which move on to the base when the support 17/43 is tilted and permit an easy rolling action of said support.

FIG. 7 shows an example of applying the invention wherein a platform rests on four supports. The pneumatic tubes 6 of the lifting devices are connected to a switchboard 55 which in turn is connected by a tube 55 to a compressed air container, e.g. an air-supply container for the brakes of a heavy lorry. The switchboard includes a pressure-limiting valve so that the lifting devices cannot be overloaded. The compressed air is first delivered to a switch valve 56 acting as an air-release valve and from there via the stopcocks 57 to the individual lifting devices.

All the lifting devices are controlled either manually or mechanically by the valve 56. In the position inflation" the valve delivers the compressed air to the bellows. In the position 37 deflation the supply of compressed air is checked and the tubes 6 simultaneously deflated. The air-release valves 8 of the individual lifting devices then discharge the compressed air from the bellows directly into the open air. Finally, the valve 56 is set at deflation." Naturally individual lifting devices can also be controlled by the valves 57 so that all factors can be taken into account when loads are raised and lowered.

if the lifting apparatus is to be constantly conveyed in the vehicle, short lever supports for example can be used which are positioned in a guide piece which is rigidly or pivotably attached to the platform and which, like the lever support in FIG. 6, has a pawl so that the load can be reduced. The lifting devices can then be attached to these guide pieces. When raised the lifting devices press the toothed pole out and downwards.

lclaim:

l. A lifting device adapted to perform in a first and second switched condition comprising:

an upstanding guide post having a series of openings therealong;

a. rigid load supporting frame carried by said guide post for step-by-step movement therealong;

an inflatable and deflatable bellows for driving said load supporting frame and connected at one end to said frame;

a lever arm pivotably supported by said load supporting frame and operatively connected at one end to the other end of said bellows to be pivoted when said bellows is inflated and deflated; and upper and lower catches, one of which is pivotably carried by the other end of said lever, which engage in said guide post openings for stepping said load supporting frame therealong, said catches being switchable for reversing the step-by-step movement of said supporting frame; whereby when said device is in a first switched condition, said load supporting frame is moved in one direction when said bellows is inflating and when said device is in a second switched condition said load supporting frame is moved in the other direction when said bellows is deflatmg. 2. A lifting device as claimed in claim 1 in which said lever is pivotably joined to said frame by tie rods rotatably fastened thereto and an upper one of said catches is guided by a pin throtjghslot means in said frame. I

3. lifting device as claimed 11'] claim 1 in which a first pawl is provided with a tooth and is rotatably mounted on the pivot pin of an upper one of said catches, said first pawl bearing under the influence of a spring against a lower catch, said lower catch having a projection in such a manner that when the lifting device is lowering, the tooth moves into the vicinity of said projection, and a second pawl is rotatably mounted on said frame, said second pawl bearing under the influence of a spring with its free end against said upper catch, said upper catch having a projection in order to check it in its position, and a control lever is mounted on said frame and controls said first pawl via a cam in such a manner that said first pawl can be alternately pivoted away from said lower catch or brought to bear against it.

4. A lifting device as claimed in claim 1 in which said device is releasably fastened to said guide which comprises a toothed or punched pole.

5. A lifting device as claimed in claim 1 in which said frame is fitted with guide jaws which are pivotably mounted in pairs and engage in a pivoted position in U-shaped sections of said guide and each pair of said jaws is provided with a lever in order to swing the guide jaws out which can bear against the frame and which is secured in a bearing position against rotation.

6. A lifting device as claimed in claim 1 in which the top and bottom of said frame are provided with eyelets in which the load can be suspended.

7. A lifting device as claimed in claim 6 in which a support is provided for supporting the load, said support being fastened to a sliding piece which encloses said guide and can be releasably connected to said frame of the lifting device.

8. A lifting device as claimed in claim 7, in which the sliding piece has a pawl for engagement with said guide.

9. A lifting device as claimed in claim 1, in which said guide is provided with a base plate on which are mounted roller means which move on the ground when the device is tilted.

10. A lifting device as claimed in claim 1 in which several of said devices are connected by tubes to a common switch cabinet which in turn is connected by an air-release valve to a pneumatic delivery pipe. 

1. A lifting device adapted to perform in a first and second switched condition comprising: an upstanding guide post having a series of openings therealong; a rigid load supporting frame carried by said guide post for step-by-step movement therealong; an inflatable and deflatable bellows for driving said load supporting frame and connected at one end to said frame; a lever arm pivotably supported by said load supporting frame and operatively connected at one end to the other end of said bellows to be pivoted when said bellows is inflated and deflated; and upper and lower catches, one of which is pivotably carried by the other end of said lever, which engage in said guide post openings for stepping said load supporting frame therealong, said catches being switchable for reversing the step-by-step movement of said supporting frame; whereby when said device is in a first switched condition, said load supporting frame is moved in one direction when said bellows is inflating and when said device is in a second switched condition said load supporting frame is moved in the other direction when said bellows is deflating.
 2. A lifting device as claimed in claim 1 in which said lever is pivotably joined to said frame by tie rods rotatably fastened thereto and an upper one of said catches is guided by a pin through slot means in said frame.
 3. A lifting device as claimed in claim 1 in which a first pawl is provided with a tooth and is rotatably mounted on the pivot pin of an upper one of said catches, said first pawl bearing under the influence of a spring against a lower catch, said lower catch having a projection in such a manner that when the lifting device is lowering, the tooth moves into the vicinity of said projection, and a second pawl is rotatably mounted on said frame, said second pawl bearing under the influence of a spring with its free end against said upper catch, said upper catch having a projection in order to check it in its position, and a control lever is mounted on said frame and controls said first pawl via a cam in such a manner that said first pawl can be alternately pivoted away from said lower catch or brought to bear against it.
 4. A lifting device as claimed in claim 1 in which said device is releasably fastened to said guide which comprises a toothed or punched pole.
 5. A lifting device as claimed in claim 1 in which said frame is fitted with guide jaws which are pivotably mounted in pairs and engage in a pivoted position in U-shaped sections of said guide and each pair of said jaws is provided with a lever in order to swing the guide jaws out which can bear against the frame and which is secured in a bearing position against rotation.
 6. A lifting device as claimed in claim 1 in which the top and bottom of said frame are provided with eyelets in which the load can be suspended.
 7. A lifting device as claimed in claim 6 in which a support is provided for supporting the load, said support being fastened to a sliding piece which encloses said guide and can be releasably connected to said frame of the lifting device.
 8. A lifting device as claimed in claim 7, in which the sliding piece has a pawl for engagement with said guide.
 9. A lifting device as claimed in claim 1, in which said guide is provided with a base plate on which are mounted roller means which move on the ground when the device is tilted.
 10. A lifting device as claimed in claim 1 in which several of said devices are connected by tubes to a common switch cabinet which in turn is connected by an air-release valve to a pneumatic delivery pipe. 